Be it known that I, CHARLESR. FLETCHER, a citizen of the United States, residing at Boston, in the county of Su'fiolk and State of Massachusettahave invented certain newand useful Improvements in Methods of Electrodeposition of Metals, of which the following. is a specification, reference being had to the drawings accompanying and forming a part of the same.

My invention relates to an' electrolytic method for the more rapid and uniform coating of metal sheets-for instance, iron or steelwith another metal or'alloy'b'y electrodeposition-for instance, copper or brass and other metals.

The ordinary method in use hitherto has been simply to suspend the sheet to be electrocoated from a horizontal bar or from a wire 2a in an electrolyte, the sheet serving as a cathode, and to deposit the coating by passing a suitable current of electricity from an anode through the electrolyte to the cathode-sheet. The electrocoating of iron or'steel sheets by this method has been very slow, and it has been Well-nigh impossible to properly coat them with copper by reason of the evolution of gas, which persists in adhering to the surface of the iron or steel or when'a considerable current density is employed'of the oxidizing of the copper upon the iron sheets, commonlytermed burning. In'the Letters Patent granted to me on October 9,.1894:, and numbered 527,110, I have described the sev- 5 oral and great advantages of my invention of attaching metal sheets to a rotating cathodebase in the process of electrocoating said sheets. My present invention has the additional advantage of efiecting the more rapid o electrodeposition of the metal or metals by reason of the arrangement of an interior anode or series of interior anodes within a rotating cathode. A rotating cathode-base is preferably used, consisting of a frame or skele- 5 ton to which the sheets of iron or steel or of other metals are attached, so that both surfaces can' be subjected to'the simultaneous electrodeposition of metal .or metals there- SerialNo.18,'322. (No model.)

fipon and uniform stirring of the electrolyte maintained.

Myinvention will'be further described with reference to the accompanying drawings, in which- Figure 1 is a perspective view of the ele'ctrolytic apparatus which I employ incarrying my iuvention'into effect, one end of the vet or tank which contains the solution being broken awayto better illustrate the construction. Fig. 2 is a vertical section of the same. Fig. 3 is a verticalsec'tion of a similar apparatus, showing the inner and outer anodes connected with two separate sources of electricity and showing the ends of the horizontally-arranged bars of the cathode-frame. Fig. 4 is a view of one of the notched pins by means of which the metal sheets to be electrocoated are secured to the rotating cathodebase. Figs. 5, 6, 7, 8, and 9 are transverse vertical sections of different forms of anodes adapted to be placed within the rotating cathode-base.

In the said drawings, 10 is an electrolytic vet for containing a suitable electrolytic solution. I suspend upon a revoluble roller 12 a cat-hode-baselat, which is partly immersed in said solution and is adapted to be rotated by the roller 12 or byother suitable means. This cathode-base is formed of several rings 15, of metal, preferably of copper or of brass,

about three inches wide and about one inch thick, connected and held together by rods,

16, preferably of metal, which may be round or rectangular, about one inch in diameter, and which are horizontally arranged and serve my electrochemical requirements by hiding the stirring of the portion of the electrolyte near the surface of the sheets. In the said rods I insert metal pins 18, to which the sheets 19 that are to be electrocoated are attached by inserting the edges of said sheets into slight cuts or grooves 20, Fig. 4, in the said pins 18, preferably after bending the sheets and springing themagainst said pins, which also serve as electrical conductors. These pins need not necessarily be opposite to each other, and they may be formed or bent into convenient shapes or angles. They may be soldered upon or screwed in or attached to the cathode-base, according as it is made of wood or mineral for instance, slate-or of metal rods. When made up of wood or slate, I employ metal bands upon the circumference of the rings and connect the metal hands by wires to the pins 18 for an electrical circuit. The sheets are arranged in such manner upon the cathode-frame as to present opposing edges to the electrolyte.

The rods or strips 16 are not always equidistant from each other, but vary in thickness and in number in the construction of the frame or cathode-base according to the size and thickness of the attached sheets. Because the density of a liquid metallic electrolyte constantly tends to become greater at the bottom of the electrolytic vat there must be some provision for maintaining uniformity of the electrolyte. To so maintain the electrolyte, recourse has been in electroretining work usually to air forced into the electrolyte; but I prefer my mechanical means, having foundthat when my sheets are attached to the cathode-frame the horizontal edges of the sheets, together with the horizontal edges of the cathode-frame, (or edges other than those which move in a vertical plane,) are sufficient to maintain the uniformity of the electrolyte and to enable the production of, in the case of copper and steel sheets, copper-steel sheets that may be soldered and sharply worked and also drawn into cartridges and even deeply spun without disruption or blistering of the copper, as has hitherto been the case, because of the occluded hydrogen gas. In my Letters Patent of October 9, 1894, numbered 527,110, this motion of the electrolyte and resulting uniformity was aided by the horizontally-arranged wires and plugs, which also served to support sheets loosely upon the cathode-base. In my present invention instead of varying the size of said wires I omit them and vary the thickness of the horizontally-arranged partsof the cathode-frame, so as to maintain, with the movementgiven to the electrolyteby the horizontal edges of the moving attached sheets, the desirable uniformity of the electrolyte. Thus I have a skeleton cathode frame or base, to which are attached the sheets of metal which are to receive the electrocoating in such manner that both surfaces are exposed to direct electrolytic action. The cathode-frame is usually cylindrical; but my invention is applicable to a cathode-frame of any form, which repeatedly passes from below upward and from above downward, the anodes oppositely disposed relatively to the repeated path of the sheets attached to it, the object being chiefly to save time by the simultaneous electrocoating of both surfaces of the attached sheets 19 by reason of the placing of one or more interior anodes 21 within the rotating skeleton cathode-base in the electrolytic vat 10 and to repeatedly stir the electrolyte. I preferably arrange curved anodes 23 23 outside of the cathode-frame 14 and connect the several outside and inside anodes by means of Wires 24 and contact-brushes 25 with a suitable source of electricity, as indicated at 26, preferably dynamo electrical machinery. I do not, however, limit my invention to the employment of a single source of electricity, as my invention is especially suited to the employment of different sources of electricity, as indicated at 27 28, which may be connected by means of wires 29 30 and contactbrushes 25 with the cathode-frame and by suitable conducting-wires completing the circuit with the outside and inside anodes, as shown in Fig. 3'that is, the outside anodes 23 23 may be connected with one source of electricity and the inside anode or anodes 21 may be connected with a weaker or a stronger source of electricity calculated to vary the electrodeposition either in the quality of metal or rapidity of deposition upon either surface of. the attached sheets, the edges receiving a good deposit. Apparatus in which currents from different sources of electricity are employed are shown and described in Letters Patent granted to me on November 1, 1892, No. 485,343, and on June 20, 1893, No. 499,726.- Two independent sources of electricity are preferably employed,for the reason that with the dynamo electrical machinery available the volume and the pressure of the currents can be better sustained than by resistance-coils, which vary the current as they become heat-ed, so as to require constant attention during electrodeposition on any considerable scale.

The interior anode may be made up of rods or bars contiguous or somewhat separated from each other, but suitably connected with conductors to convey and to distribute the necessary currents of electricity. This interior anode when single is usually a solid or hollow casting supported inside of the cathodebase 14 upon bearings attached to opposite ends of the vat. I sometimes prefer an interior anode made up of separate parts, as shown in Fig. 5, in which case I attach a series of bars or rods to two circular metallic disks 31, which are provided with journals supported in suitable bearings. Other forms of interior anodes, either solid or hollow and of circular or polygonal form in cross-section, as shown in Figs. 6, 7, 8, and 9, may be employed, as may be found convenient or desirable. The rings 15 are provided with holes 32, in which are fitted removable plugs 33, against which the plates 19 abut, said plugs serving to prevent lateral movement of the plates while being rotated in the electrolyte.

By means of my invention I am thus enabled to more rapidly and uniformly coat with metal free from occluded hydrogen gas both surfaces of the attached sheets by electrodeposition upon both of their surfaces simultaneously,.also to vary the electrodeposition upon the surfaces of the attached sheets, by proper regulation of the source or sources ofelectricity and the density of the current upon the surfaces of the attached sheets.

Having thus described my invention, what I claim isl. The herein-described method of electrocoating metal sheets with metal or metals, which consists in attaching the sheets to a cathodeframe or base and causing them,when arranged in such manner upon the cathodeframe as to present opposing edges to the elec-. trolyte, to pass and repass in an electrolyte through the electrodepository field or range of anodes oppositely disposed relatively to the path of the sheets, whereby the edges of thesheets and of the cathode-frame cause repeated stirring of the electrolyte in the said eleotrodepository field, substantially as described.

2. The method of electrocoating metal sheets with metal or metals, which consists in bending the sheets and attaching the curved sheets to a cathode frame or base, and then repeatedly rotating said curved sheets, arranged in such manner upon thecathodeframe as to present opposing edges to the electrolyte, in an electrolyte and simultaneously electrocoat-ing both surfaces of the sheets by means of electric currents passed CHARLES R. FLETCHER; In presence of I P. E. TESCHEMAGHER, LILLIAN I. BASFORD.